Before commit 3fa2bb31 this type appeared in the catalogs to
select which of several block storage mechanisms each relation
used.
New features under development propose to revive the concept of
different block storage managers for new kinds of data accessed
via bufmgr.c, but don't need to put references to them in the
catalogs. So, avoid useless maintenance work on this type by
dropping it. Update some regression tests that were referencing
it where any type would do.
Discussion: https://postgr.es/m/CA%2BhUKG%2BDE0mmiBZMtZyvwWtgv1sZCniSVhXYsXkvJ_Wo%2B83vvw%40mail.gmail.com
This introduces the concept of table access methods, i.e. CREATE
ACCESS METHOD ... TYPE TABLE and
CREATE TABLE ... USING (storage-engine).
No table access functionality is delegated to table AMs as of this
commit, that'll be done in following commits.
Subsequent commits will incrementally abstract table access
functionality to be routed through table access methods. That change
is too large to be reviewed & committed at once, so it'll be done
incrementally.
Docs will be updated at the end, as adding them incrementally would
likely make them less coherent, and definitely is a lot more work,
without a lot of benefit.
Table access methods are specified similar to index access methods,
i.e. pg_am.amhandler returns, as INTERNAL, a pointer to a struct with
callbacks. In contrast to index AMs that struct needs to live as long
as a backend, typically that's achieved by just returning a pointer to
a constant struct.
Psql's \d+ now displays a table's access method. That can be disabled
with HIDE_TABLEAM=true, which is mainly useful so regression tests can
be run against different AMs. It's quite possible that this behaviour
still needs to be fine tuned.
For now it's not allowed to set a table AM for a partitioned table, as
we've not resolved how partitions would inherit that. Disallowing
allows us to introduce, if we decide that's the way forward, such a
behaviour without a compatibility break.
Catversion bumped, to add the heap table AM and references to it.
Author: Haribabu Kommi, Andres Freund, Alvaro Herrera, Dimitri Golgov and others
Discussion:
https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.dehttps://postgr.es/m/20160812231527.GA690404@alvherre.pgsqlhttps://postgr.es/m/20190107235616.6lur25ph22u5u5av@alap3.anarazel.dehttps://postgr.es/m/20190304234700.w5tmhducs5wxgzls@alap3.anarazel.de
The "name" comparison operators now all support collations, making them
functionally equivalent to "text" comparisons, except for the different
physical representation of the datatype. They do, in fact, mostly share
the varstr_cmp and varstr_sortsupport infrastructure, which has been
slightly enlarged to handle the case.
To avoid changes in the default behavior of the datatype, set name's
typcollation to C_COLLATION_OID not DEFAULT_COLLATION_OID, so that
by default comparisons to a name value will continue to use strcmp
semantics. (This would have been the case for system catalog columns
anyway, because of commit 6b0faf723, but doing this makes it true for
user-created name columns as well. In particular, this avoids
locale-dependent changes in our regression test results.)
In consequence, tweak a couple of places that made assumptions about
collatable base types always having typcollation DEFAULT_COLLATION_OID.
I have not, however, attempted to relax the restriction that user-
defined collatable types must have that. Hence, "name" doesn't
behave quite like a user-defined type; it acts more like a domain
with COLLATE "C". (Conceivably, if we ever get rid of the need for
catalog name columns to be fixed-length, "name" could actually become
such a domain over text. But that'd be a pretty massive undertaking,
and I'm not volunteering.)
Discussion: https://postgr.es/m/15938.1544377821@sss.pgh.pa.us
I noticed that all non-composite, non-array entries in pg_type.dat
had descr strings, except for "json" and the pseudo-types. The
lack for json seems certainly an oversight, and there's surely
little reason to not have entries for the pseudo-types either.
So add some.
"make reformat-dat-files" turned up some formatting issues in
pg_amop.dat, too, so fix those in passing.
No catversion bump since the backend doesn't care too much what is
in pg_description.
This eliminates some more tedium in adding new catalog entries,
specifically the need to set up an array type when adding a new
built-in data type. Now it's sufficient to assign an OID for the
array type and write it in an "array_type_oid" metadata field.
You don't have to fill the base type's typarray link explicitly, either.
No catversion bump since the contents of pg_type aren't changed.
(Well, their order might be different, but that doesn't matter.)
John Naylor, reviewed and whacked around a bit by
Dagfinn Ilmari Mannsåker, and some more by me.
Discussion: https://postgr.es/m/CAJVSVGVTb6m9pJF49b3SuA8J+T-THO9c0hxOmoyv-yGKh-FbNg@mail.gmail.com
Use the term "system catalog" rather than "system relation" in assorted
places where it's clearly referring to a table rather than, say, an
index. Use more natural word order in the header boilerplate, improve
some of the one-liner catalog descriptions, and fix assorted random
deviations from the normal boilerplate. All purely neatnik-ism, but
why not.
John Naylor, some additional cleanup by me
Discussion: https://postgr.es/m/CAJVSVGUeJmFB3h-NJ18P32NPa+kzC165nm7GSoGHfPaN80Wxcw@mail.gmail.com
Write ',' and ';' for typdelim values instead of the obscurantist
ASCII octal equivalents. Not sure why anybody ever thought the
latter were better; maybe it had something to do with lack of
a better quoting convention, twenty-plus years ago?
Reassign a couple of high-numbered OIDs that were left in during
yesterday's mad rush to commit stuff of uncertain internal
temperature.
The latter requires a catversion bump, though the former wouldn't
since the end-result catalog data is unchanged.
Historically, the initial catalog data to be installed during bootstrap
has been written in DATA() lines in the catalog header files. This had
lots of disadvantages: the format was badly underdocumented, it was
very difficult to edit the data in any mechanized way, and due to the
lack of any abstraction the data was verbose, hard to read/understand,
and easy to get wrong.
Hence, move this data into separate ".dat" files and represent it in a way
that can easily be read and rewritten by Perl scripts. The new format is
essentially "key => value" for each column; while it's a bit repetitive,
explicit labeling of each value makes the data far more readable and less
error-prone. Provide a way to abbreviate entries by omitting field values
that match a specified default value for their column. This allows removal
of a large amount of repetitive boilerplate and also lowers the barrier to
adding new columns.
Also teach genbki.pl how to translate symbolic OID references into
numeric OIDs for more cases than just "regproc"-like pg_proc references.
It can now do that for regprocedure-like references (thus solving the
problem that regproc is ambiguous for overloaded functions), operators,
types, opfamilies, opclasses, and access methods. Use this to turn
nearly all OID cross-references in the initial data into symbolic form.
This represents a very large step forward in readability and error
resistance of the initial catalog data. It should also reduce the
difficulty of renumbering OID assignments in uncommitted patches.
Also, solve the longstanding problem that frontend code that would like to
use OID macros and other information from the catalog headers often had
difficulty with backend-only code in the headers. To do this, arrange for
all generated macros, plus such other declarations as we deem fit, to be
placed in "derived" header files that are safe for frontend inclusion.
(Once clients migrate to using these pg_*_d.h headers, it will be possible
to get rid of the pg_*_fn.h headers, which only exist to quarantine code
away from clients. That is left for follow-on patches, however.)
The now-automatically-generated macros include the Anum_xxx and Natts_xxx
constants that we used to have to update by hand when adding or removing
catalog columns.
Replace the former manual method of generating OID macros for pg_type
entries with an automatic method, ensuring that all built-in types have
OID macros. (But note that this patch does not change the way that
OID macros for pg_proc entries are built and used. It's not clear that
making that match the other catalogs would be worth extra code churn.)
Add SGML documentation explaining what the new data format is and how to
work with it.
Despite being a very large change in the catalog headers, there is no
catversion bump here, because postgres.bki and related output files
haven't changed at all.
John Naylor, based on ideas from various people; review and minor
additional coding by me; previous review by Alvaro Herrera
Discussion: https://postgr.es/m/CAJVSVGWO48JbbwXkJz_yBFyGYW-M9YWxnPdxJBUosDC9ou_F0Q@mail.gmail.com
